EP1328481B1 - Verfahren zum umformen des ziehendes einer vorform für optische fasern - Google Patents

Verfahren zum umformen des ziehendes einer vorform für optische fasern Download PDF

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Publication number
EP1328481B1
EP1328481B1 EP00970525A EP00970525A EP1328481B1 EP 1328481 B1 EP1328481 B1 EP 1328481B1 EP 00970525 A EP00970525 A EP 00970525A EP 00970525 A EP00970525 A EP 00970525A EP 1328481 B1 EP1328481 B1 EP 1328481B1
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EP
European Patent Office
Prior art keywords
preform
draw
tip
optical fiber
furnace
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
EP00970525A
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English (en)
French (fr)
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EP1328481A1 (de
Inventor
Tony A. Craft
Kenneth J. Kelmer
Theresa L. Watkins
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Corning Inc
Original Assignee
Corning Inc
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Filing date
Publication date
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Publication of EP1328481B1 publication Critical patent/EP1328481B1/de
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Classifications

    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B37/00—Manufacture or treatment of flakes, fibres, or filaments from softened glass, minerals, or slags
    • C03B37/01—Manufacture of glass fibres or filaments
    • C03B37/02—Manufacture of glass fibres or filaments by drawing or extruding, e.g. direct drawing of molten glass from nozzles; Cooling fins therefor
    • C03B37/025—Manufacture of glass fibres or filaments by drawing or extruding, e.g. direct drawing of molten glass from nozzles; Cooling fins therefor from reheated softened tubes, rods, fibres or filaments, e.g. drawing fibres from preforms
    • C03B37/029—Furnaces therefor
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B37/00—Manufacture or treatment of flakes, fibres, or filaments from softened glass, minerals, or slags
    • C03B37/01—Manufacture of glass fibres or filaments
    • C03B37/02—Manufacture of glass fibres or filaments by drawing or extruding, e.g. direct drawing of molten glass from nozzles; Cooling fins therefor
    • C03B37/025—Manufacture of glass fibres or filaments by drawing or extruding, e.g. direct drawing of molten glass from nozzles; Cooling fins therefor from reheated softened tubes, rods, fibres or filaments, e.g. drawing fibres from preforms
    • C03B37/027—Fibres composed of different sorts of glass, e.g. glass optical fibres
    • C03B37/02772—Fibres composed of different sorts of glass, e.g. glass optical fibres shaping the preform lower end or bulb, e.g. pre-gobbing, controlling draw bulb shape, or preform draw start-up procedures
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B37/00—Manufacture or treatment of flakes, fibres, or filaments from softened glass, minerals, or slags
    • C03B37/01—Manufacture of glass fibres or filaments
    • C03B37/012—Manufacture of preforms for drawing fibres or filaments
    • C03B37/01205—Manufacture of preforms for drawing fibres or filaments starting from tubes, rods, fibres or filaments
    • C03B37/01225—Means for changing or stabilising the shape, e.g. diameter, of tubes or rods in general, e.g. collapsing
    • C03B37/01251—Reshaping the ends
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B2205/00—Fibre drawing or extruding details
    • C03B2205/47—Shaping the preform draw bulb before or during drawing

Definitions

  • the invention relates to a method for manufacture of an optical fiber preform and optical fiber, and more particularly to a method for preparing a preform's tip to expedite fiber draw.
  • the starting point in the method for manufacturing optical fiber is the preparation of an elongated, cylindrical quartz glass body, doped accordingly to provide the desired refractive index profile in the optical fiber.
  • This so-called "preform” is introduced very slowly, by means of a downfeed device, into the high-temperature heating furnace of a draw tower.
  • the preform is heated at its terminal end to temperatures sufficiently high to cause the tip of the preform to be gradually transformed to a honey-like consistency.
  • a glass gob melts off the preform by the influence of heat and gravity. Then an operator hand strips additional trash glass from the preform until a portion of the preform being drawn from contains good quality glass.
  • the draw tip consists of a generally tapering transition area located between the quartz glass cylinder portion of the preform and the thin fiber strand being drawn from the lowermost tip of the preform.
  • the dimensions of the drawn fiber depend on the high-temperature furnace and the individual drawing conditions. However, a preferred glass strand of approximately 125 ⁇ m in diameter is continuously drawn off from the preform. It then passes through the cooling tube and passes through the coating system, which applies the protective sheath (coating).
  • the coating system is located in the drawing tower below a diameter testing device. At the end of the draw tower, the fiber is wound onto a spool.
  • JP- A - 08 310 825 describes a method of manufacturing an optical fiber preform according to the preamble of claim 1 below.
  • a pregobbing method is used for the pregobbing treatment of an optical fiber preform to provide a desired pre-optimized tip geometry prior to insertion into a draw apparatus.
  • the method provides a preform having an optimized shape draw tip and permits, for example, the glass mass of an optical fiber preform that is not suitable for fiber drawing to melt off very rapidly and efficiently.
  • the pregobbing operation is performed in a pregobbing apparatus separate from the draw furnace of the draw tower.
  • the pregobbing is accomplished in an "off line" fashion, i.e., in another apparatus, the fiber throughput from the draw apparatus is increased.
  • preforms including pre-optimized leading end tips result in considerably shortened downtime for the optical fiber draw apparatus.
  • a method for manufacturing an optical fiber preform comprising heating a consolidated optical fiber preform with a heating apparatus, preferably an induction heating apparatus having a first temperature profile to allow a gob to drop under the influence of heat and gravity, removing glass from the preform until a draw tip having a pre-optimized shape is formed, and transferring the preform to a draw furnace of a draw apparatus.
  • the pre-optimized shape includes a tip taper having a tip length to change in radius ratio of between about 5 to about 12, and most preferably between about 6 to about 9.
  • the "pre-optimized" tip shape as the term is used herein means a tip that has been preshaped such that it has a taper approximately equal to what it will have when fiber is being drawn therefrom in the.draw apparatus.
  • a method for manufacturing an optical fiber comprising the steps of heating a plurality of consolidated optical fiber preforms within a plurality of pregobbing apparatus, each apparatus including a furnace having a first temperature profile to form pre-optimized shape preform tip, with the defined tip tapes, on each of the plurality of preforms, and transferring the plurality of preforms to a plurality of draw apparatus, each draw apparatus including a furnace and drawing optical fiber therefrom, the plurality of draw furnaces each having a second temperature profile substantially equal to the first temperature profile. Accordingly, a large number of draw apparatus may be supplied with pro-optimized preforms by a small number of pregobbing apparatus.
  • FIG. 1 An apparatus for performing the pregobbing operation off-line (in another apparatus other than the draw furnace) is shown schematically in Fig. 1.
  • the pregobbing apparatus 20 is used for melting off the initial trash quartz glass mass from the preform 22, i.e., that glass at the ends of the preform that is not suitable for drawing adequate production quality fiber therefrom.
  • the apparatus used in the method optimizes the shape of the leading end (tip) of the preform 22 such that when transferred to the draw tower, drawing of fiber may readily commence.
  • the apparatus 20 preferably includes an induction furnace 24 which preferably has a temperature profile identical to the furnace 42 utilized in the draw tower 40 (Fig. 6).
  • the pregobbing furnace 24 produces a tapered draw tip 32 on the preform 22 (Fig.
  • Fig. 4 illustrates a non-pregobbed and pregobbed tips and their relative dimensions.
  • the pre-optimized tip has a tip length to radius change ratio (as measured from the start of the tip to the end of the tip) of between about 5 to about 12, and preferably between about 6 to about 9.
  • the tip length is measure from the start of the taper intersecting the cylindrical part of the preform to the terminal leading end of the preform.
  • the change in radius is measured from the start of the taper as just defined to the radius at the terminal leading end.
  • the tip diameter may be very small, on the order of a few mm to about 15 mm.
  • the pregobbing heating furnace24 has a cylindrical heating chamber 28, heat insulation 30 surrounding the heating chamber, and an induction coil 62 surrounding the chamber and preform 22 and providing a hot zone 60 for heating the leading tip 32 of the preform 22.
  • the induction coil, size and shape of the chamber, and insulation provided are such that the temperature profile of the pregobbing furnace 24 adjacent the tip is substantially identical to that of the draw furnace 42 (Fig. 6). This is accomplished in practice by having the internal components of the furnace be identical and adjusting the temperature controls for any slight differences.
  • the consolidated preform 22 is provided as indicated in step 35 by traversing the preform 22 roughly into position by an overhead crane apparatus or track 34.
  • the preform 22 may have come directly from a consolidation process or from an intermediate holding oven.
  • the preform 22 is housed within a carrier box 36 which surrounds the preform such that it is protected from contamination and collisions during transit to the pregobbing apparatus 20.
  • An operator 52 disconnects the preform 22 from the track 34 and mounts the preform to a handle 38 extending from a motorized down feed apparatus 44.
  • the down feed apparatus 44 is preferably mounted to a vertically moveable carriage 46 or other moveable structure.
  • the down feed apparatus 44 extends downwardly from the lower end of the carriage 46 and the carriage operatively slides vertically along rails 48 to allow the preform to be raised and lowered as commanded.
  • the gross vertical motion of the preform 22 and carriage 46 relative to the apparatus frame 54 are controlled by a drive motor 50 mounted to the frame 54.
  • the motor 50 Upon initiation by the operator 52 or 53, the motor 50 begins to rotate a lead screw 56 that parallels the rails 48.
  • Lead screw 56 cooperates with a threaded portion (not shown) mounted in the carriage 46. Rotation of the lead screw 56 causes movement of the vertical position of carriage 46 thereby causing the carriage to move along the rails 48 and, thus, change the vertical position the preform 22.
  • the carriage 46 When loading the preform 22, the carriage 46 would be positioned at the location shown dotted and labeled "A.” Once the preform 22 is suitably loaded onto the handle 38, the carrying case 36 is removed and put aside, and the preform 22 is then transferred into the pregobbing furnace 24 as indicated in step 37 (Fig. 5) by lowering the preform 22 into the entrance 29 (Fig. 4) of the pregobbing furnace 24. This is accomplished by rotating lead screw 56 such that carriage 46 slides downward along the slide rails 48.
  • the glass preform 22 is moved downward until the lowest portion of the tip 32 is positioned roughly within the hot zone 60 of the furnace 24 (Fig. 4).
  • the lower preform 22 shown in Fig. 1 is shown being lowered into the chamber 28 of furnace 24
  • the preform 22 is allowed to remain at this position until the tip 32 softens to the point where a small gob 27 of glass drops off from the preform 22 by the action of heat and gravity alone.
  • the gob drops through the exit 31 and into the trash.
  • the rough position of the preform 22 within the furnace 24 is determined by a mirror.
  • the preform 22 is driven deeper into the hot zone 60 by down feed 44 such that the whole tip 32 (Fig. 2) is placed directly in the hot zone 60 of furnace 24.
  • a second larger gob drops by the influence of heat and gravity.
  • the operator 53 pulls on the larger gob with scissors or other like tool and continues to strip trash glass with seeds or other defects from the preform 22 and appropriately scores and discards the trash glass as it drops and solidify. Both of these gob removal steps are accomplished in step labeled 39 of Fig. 5. However, it should be understood that there may be one or multiple gobs that drop depending on the initial conditions and the rate of stripping provided by the operator.
  • the process is stopped and the preform 22 is removed from the pregobbing furnace 24.
  • the hot zone of the furnace is preferably maintained at a temperature of between 1800 °C and 2000 °C, and more preferably between 1900 °C and 1950 °C.
  • a small gob 27 will generally drop within about 25 min.
  • the entire pregobbing process (including stripping) takes about 45-50 min.
  • the preform 22 is preferably placed back in the protective case 36.
  • Preform 22 is then transferred in accordance with step 41 of Fig. 5 to a draw tower 40 (Fig. 6) where fiber is to be drawn therefrom.
  • the preform 22 is preferably transferred by an overhead crane or monorail system.
  • the preform 22 is removed from the carrier 36, connected to a draw furnace handle 158 and lowered into the draw furnace 42.
  • the preform 22 with optimized draw tip 32 is driven into the hot zone 160 of the chamber 128 maintained with substantially the same temperature profile as that of the pregobbing furnace 24.
  • Induction coil(s) 162 surrounding the preform 22 induce heat into the susceptor 64 to provide the hot zone 60 of approximately 1800°C-2200°C.
  • step 43 Fig.
  • optical fiber 65 sufficient tension is provided by a tractor or other tension providing means to draw optical fiber 65 from the preform 22.
  • the optical fiber 65 preferably has a diameter of approximately 0.125 ⁇ m.
  • the fiber 65 may then be cooled, coated and wound onto a spool as is conventional practice.
  • a plurality of pregobbing apparatus 220, 320 may be utilized to supply preforms with pre-optimized shape tips to a plurality of draw apparatus 240, 340, 440, 540. Because the pregobbing step generally takes less time than drawing fiber from a preform, there are a lesser number of pregobbing apparatus than draw apparatus.
  • a plurality of consolidated optical fiber preforms are heated within a plurality of pregobbing apparatus 220, 320.
  • Each apparatus 220, 230 includes an induction furnace as shown in Fig. 4 having a first temperature profile to form pre-optimized shape preform tips on each of a plurality of preforms.
  • each of the plurality of draw apparatus 240-540 includes an induction furnace as heretofore described.
  • the preforms with pre-optimized tips are transferred to a plurality of draw apparatus 240-540 by any of the paths (a-h) shown.
  • any pregobbing apparatus may supply any draw apparatus.
  • the plurality of draw furnaces 240-540 each have a second temperature profile substantially equal to the first temperature profile.
  • a small number of pregobbing apparatus may be utilized to supply pre-optimized preforms to a much larger number of draw apparatus. It should be recognized that although two pregobbing apparatus are shown and four draw apparatus, a smaller number or larger number of draw apparatus may be utilized as dictated by production requirements. Further, a larger number of pregobbing apparatus may be employed.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Geochemistry & Mineralogy (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • Manufacture, Treatment Of Glass Fibers (AREA)

Claims (9)

  1. Verfahren zur Herstellung einer optischen Faservorform mit den Schritten:
    a) Erhitzen einer verfestigten optischen Faservorform (22) mit einem Heizgerät (20) mit einem ersten Temperaturprofil,
    b) Entfernen von Glas von der Vorform, bis eine Ziehspitze (32) mit einer Spitzenverjüngung ausgebildet wird, und
    c) Überführen der Vorform mit der Ziehspitze in einen Ziehofen (42) eines Ziehgerätes (40),
    dadurch gekennzeichnet, dass:
    in Schritt a) ein Glastropfen (27) unter dem Einfluss von Wärme und Schwerkraft tropfen kann, und dass Schritt b) das Entfernen von zusätzlichem Glas umfasst, um eine Spitzenverjüngung mit einem Verhältnis von Spitzenlänge zu Radiusänderung entlang der Länge der Spitze von zwischen ungefähr 5 bis ungefähr 12 auszubilden.
  2. Verfahren gemäß Anspruch 1, wobei der Schritt des Erwärmens durch mindestens eine Induktionsheizung (62), die die Vorform umgibt, erzielt wird.
  3. Verfahren gemäß Anspruch 1, wobei das Verhältnis zwischen ungefähr 6 bis ungefähr 9 beträgt.
  4. Verfahren gemäß Anspruch 1, wobei das Induktionsheizgerät eine Temperatur zwischen 1800°C und 2000°C beibehält.
  5. Verfahren gemäß Anspruch 1, wobei das Heizgerät eine Temperatur zwischen 1900°C und 1950°C beibehält.
  6. Verfahren zum Herstellen einer optischen Faser mit den Schritten:
    Herstellen einer Vielzahl von optischen Faservorformen durch das Verfahren irgendeines vorhergehenden Anspruchs, wobei die Vielzahl der Vorformen in eine Vielzahl von Ziehgeräten überführt wird, die jeweils einen Ofen einschließen, und
    Ziehen von optischen Fasern daraus, wobei die Vielzahl der Ziehöfen jeweils ein zweites Temperaturprofil besitzt, das im Wesentlichen gleich dem ersten Temperaturprofil ist.
  7. Verfahren gemäß Anspruch 6, wobei die Vorform innerhalb des Ziehofens (42) einem zweiten Temperaturprofil ausgesetzt wird, das im Wesentlichen identisch zu dem ersten Temperaturprofil ist.
  8. Verfahren gemäß Anspruch 6 oder 7, wobei die Ziehöfen Induktionsöfen sind.
  9. Verfahren gemäß den Ansprüchen. 6,7 oder 8, wobei es eine geringere Anzahl an Pregobbinggeräten (Glastropfenvorformungsgeräten) als an Ziehgeräten vorliegt.
EP00970525A 2000-09-29 2000-09-29 Verfahren zum umformen des ziehendes einer vorform für optische fasern Expired - Lifetime EP1328481B1 (de)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/US2000/026937 WO2002028789A1 (en) 2000-09-29 2000-09-29 Method and apparatus for reshaping the draw end of an optical fiber preform

Publications (2)

Publication Number Publication Date
EP1328481A1 EP1328481A1 (de) 2003-07-23
EP1328481B1 true EP1328481B1 (de) 2007-08-01

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EP (1) EP1328481B1 (de)
JP (1) JP4700893B2 (de)
KR (1) KR100684914B1 (de)
AU (1) AU2000279892A1 (de)
BR (1) BR0017345A (de)
CA (1) CA2424100A1 (de)
DE (1) DE60035808T2 (de)
WO (1) WO2002028789A1 (de)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20200223737A1 (en) * 2019-01-15 2020-07-16 Heraeus Quartz North America Llc Automated large outside diameter preform tipping process and resulting glass preforms
US11618708B2 (en) 2016-05-03 2023-04-04 Heraeus Quartz North America Llc Elongation method and preform for producing an optical glass component

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB0209908D0 (en) * 2002-04-30 2002-06-05 Blazephotonics Ltd A method and apparatus relating to optical fibres
DE102004039645B3 (de) 2004-08-14 2006-01-05 Heraeus Tenevo Ag Verfahren zur Herstellung eines optischen Bauteils aus Quarzglas sowie zur Durchführung des Verfahrens geeignetes Vorprodukt
CN109553293A (zh) * 2019-01-29 2019-04-02 江苏通鼎光棒有限公司 一种光纤预制棒拉锥装置及相应的拉锥方法

Family Cites Families (8)

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Publication number Priority date Publication date Assignee Title
JPS61251536A (ja) * 1985-04-26 1986-11-08 Fujitsu Ltd 光フアイバの製造方法
JPH02164738A (ja) * 1988-12-16 1990-06-25 Furukawa Electric Co Ltd:The 光ファイバの線引き方法
JPH07330362A (ja) * 1994-06-06 1995-12-19 Fujikura Ltd ガラスファイバ紡糸用母材先端の加工方法およびその装置
JPH08310825A (ja) * 1995-05-15 1996-11-26 Fujikura Ltd 光ファイバ母材の加工方法
JP3489345B2 (ja) * 1996-09-05 2004-01-19 住友電気工業株式会社 光ファイバの製造方法
WO2000076926A1 (fr) * 1999-06-14 2000-12-21 The Furukawa Electric Co., Ltd. Procede et dispositif de chauffage/usinage de l'extremite du materiau de base d'une fibre optique
JP2001019464A (ja) * 1999-07-05 2001-01-23 Sumitomo Electric Ind Ltd 光ファイバの線引き装置及び線引き方法
JP2001287926A (ja) * 2000-04-03 2001-10-16 Sumitomo Electric Ind Ltd 線引き口出し方法及び線引き装置

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11618708B2 (en) 2016-05-03 2023-04-04 Heraeus Quartz North America Llc Elongation method and preform for producing an optical glass component
US11840472B2 (en) 2016-05-03 2023-12-12 Heraeus Quartz North America Llc Elongation method and preform for producing an optical glass component
US20200223737A1 (en) * 2019-01-15 2020-07-16 Heraeus Quartz North America Llc Automated large outside diameter preform tipping process and resulting glass preforms
US11649185B2 (en) * 2019-01-15 2023-05-16 Heraeus Quartz North America Llc Automated large outside diameter preform tipping process and resulting glass preforms

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Publication number Publication date
CA2424100A1 (en) 2002-04-11
BR0017345A (pt) 2003-07-22
WO2002028789A1 (en) 2002-04-11
JP2004510671A (ja) 2004-04-08
DE60035808D1 (de) 2007-09-13
JP4700893B2 (ja) 2011-06-15
KR20040010534A (ko) 2004-01-31
KR100684914B1 (ko) 2007-02-20
DE60035808T2 (de) 2008-04-30
EP1328481A1 (de) 2003-07-23
AU2000279892A1 (en) 2002-04-15

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